Patients with acute coronary syndrome (ACS) caused by plaque erosion could benefit from antithrombotic therapy without stenting, according to results of the EROSION* study presented at the European Society of Cardiology (ESC) Congress 2016 held in Rome, Italy.

Four hundred and five patients with ACS (96.7 percent with ST-segment elevation myocardial infarction [STEMI]) participated in this single-centre (2^nd Affiliated Hospital of Harbin Medical University, Harbin, China), uncontrolled, prospective study, of which 103 (25.4 percent) were found to have plaque erosion as determined by optical coherence tomography (OCT).

Prior to catheterization, patients received aspirin (300 mg), ticagrelor (180 mg), and unfractionated heparin (100 IU/kg). They also received unfractionated or low molecular weight heparin for 3 days postcatheterization and continued dual antiplatelet therapy (aspirin 100 mg/day and ticagrelor 90 mg twice a day).

Of the 60 patients who enrolled for follow-up study at 1-month, 47 experienced a >50 percent reduction of thrombus volume (78.3 percent, 95 percent confidence interval [CI], 65.8─87.9 percent). [Eur Heart J 2016;doi:10.1093/eurheartj/ehw381; ESC 2016, FP 5031]

Thrombus volume significantly decreased by 94.2 percent (n=55; 3.7 mm³ to 0.2 mm³; p<0.001). Twenty-two patients had no visible thrombus at 1-month follow-up and two patients had major adverse cardiovascular events (MACE).

“Antithrombotic therapy without stent implantation effectively reduced thrombus volume and increased flow area without recurrent ischaemic events at 1 month,” said study author Dr Ik-Kyung Jang from Harvard Medical School, Boston, Massachusetts, US. “Randomized trials will be needed to reproduce this pilot data and to further evaluate the long-term outcome of this new treatment strategy in patients with ACS caused by plaque erosion,” he said.

“If this conservative approach without a metallic stent or polymer scaffold proves to be effective and safe, it may become a new treatment paradigm for one-fourth of patients with ACS,” said the study authors, who acknowledged that the lack of a control group (patients treated with stents) and single-centre status were among the study limitations. Furthermore, the results may not extend to other populations as a majority of the patients in this study were young Chinese males with a high prevalence of smoking.

“A significant portion of thrombotic lesions are associated with plaque erosion,” said the authors, who cited previous studies that demonstrated an incidence of 22 to 44 percent. [Thromb Haemost 2016;115:509-519] A larger lumen, preserved vascular integrity, and a platelet-rich thrombus are hallmarks of plaque erosion and differentiate it from plaque rupture, they said.